[PATCH 1/2] coreaudio: Drop support for macOS older than 10.6

[PATCH 1/2] coreaudio: Drop support for macOS older than 10.6

[Akihiko Odaki]

Mac OS X 10.6 was released in 2009.

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
---
 audio/coreaudio.c | 103 ----------------------------------------------
 1 file changed, 103 deletions(-)

diff --git a/audio/coreaudio.c b/audio/coreaudio.c
index b7c02e0e516..c5f0b615d64 100644
--- a/audio/coreaudio.c
+++ b/audio/coreaudio.c
@@ -32,10 +32,6 @@
 #define AUDIO_CAP "coreaudio"
 #include "audio_int.h"
 
-#ifndef MAC_OS_X_VERSION_10_6
-#define MAC_OS_X_VERSION_10_6 1060
-#endif
-
 typedef struct coreaudioVoiceOut {
     HWVoiceOut hw;
     pthread_mutex_t mutex;
@@ -45,9 +41,6 @@ typedef struct coreaudioVoiceOut {
     AudioDeviceIOProcID ioprocid;
 } coreaudioVoiceOut;
 
-#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
-/* The APIs used here only become available from 10.6 */
-
 static OSStatus coreaudio_get_voice(AudioDeviceID *id)
 {
     UInt32 size = sizeof(*id);
@@ -169,102 +162,6 @@ static OSStatus coreaudio_get_isrunning(AudioDeviceID id, UInt32 *result)
                                       &size,
                                       result);
 }
-#else
-/* Legacy versions of functions using deprecated APIs */
-
-static OSStatus coreaudio_get_voice(AudioDeviceID *id)
-{
-    UInt32 size = sizeof(*id);
-
-    return AudioHardwareGetProperty(
-        kAudioHardwarePropertyDefaultOutputDevice,
-        &size,
-        id);
-}
-
-static OSStatus coreaudio_get_framesizerange(AudioDeviceID id,
-                                             AudioValueRange *framerange)
-{
-    UInt32 size = sizeof(*framerange);
-
-    return AudioDeviceGetProperty(
-        id,
-        0,
-        0,
-        kAudioDevicePropertyBufferFrameSizeRange,
-        &size,
-        framerange);
-}
-
-static OSStatus coreaudio_get_framesize(AudioDeviceID id, UInt32 *framesize)
-{
-    UInt32 size = sizeof(*framesize);
-
-    return AudioDeviceGetProperty(
-        id,
-        0,
-        false,
-        kAudioDevicePropertyBufferFrameSize,
-        &size,
-        framesize);
-}
-
-static OSStatus coreaudio_set_framesize(AudioDeviceID id, UInt32 *framesize)
-{
-    UInt32 size = sizeof(*framesize);
-
-    return AudioDeviceSetProperty(
-        id,
-        NULL,
-        0,
-        false,
-        kAudioDevicePropertyBufferFrameSize,
-        size,
-        framesize);
-}
-
-static OSStatus coreaudio_get_streamformat(AudioDeviceID id,
-                                           AudioStreamBasicDescription *d)
-{
-    UInt32 size = sizeof(*d);
-
-    return AudioDeviceGetProperty(
-        id,
-        0,
-        false,
-        kAudioDevicePropertyStreamFormat,
-        &size,
-        d);
-}
-
-static OSStatus coreaudio_set_streamformat(AudioDeviceID id,
-                                           AudioStreamBasicDescription *d)
-{
-    UInt32 size = sizeof(*d);
-
-    return AudioDeviceSetProperty(
-        id,
-        0,
-        0,
-        0,
-        kAudioDevicePropertyStreamFormat,
-        size,
-        d);
-}
-
-static OSStatus coreaudio_get_isrunning(AudioDeviceID id, UInt32 *result)
-{
-    UInt32 size = sizeof(*result);
-
-    return AudioDeviceGetProperty(
-        id,
-        0,
-        0,
-        kAudioDevicePropertyDeviceIsRunning,
-        &size,
-        result);
-}
-#endif
 
 static void coreaudio_logstatus (OSStatus status)
 {
-- 
2.24.3 (Apple Git-128)

[PATCH 2/2] coreaudio: Handle output device change

[Akihiko Odaki]

An output device change can occur when plugging or unplugging an
earphone.

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
---
 audio/coreaudio.c | 327 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 236 insertions(+), 91 deletions(-)

diff --git a/audio/coreaudio.c b/audio/coreaudio.c
index c5f0b615d64..578ec9b8b2e 100644
--- a/audio/coreaudio.c
+++ b/audio/coreaudio.c
@@ -36,22 +36,26 @@ typedef struct coreaudioVoiceOut {
     HWVoiceOut hw;
     pthread_mutex_t mutex;
     AudioDeviceID outputDeviceID;
+    int frameSizeSetting;
+    uint32_t bufferCount;
     UInt32 audioDevicePropertyBufferFrameSize;
     AudioStreamBasicDescription outputStreamBasicDescription;
     AudioDeviceIOProcID ioprocid;
+    bool enabled;
 } coreaudioVoiceOut;
 
+static const AudioObjectPropertyAddress voice_addr = {
+    kAudioHardwarePropertyDefaultOutputDevice,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+};
+
 static OSStatus coreaudio_get_voice(AudioDeviceID *id)
 {
     UInt32 size = sizeof(*id);
-    AudioObjectPropertyAddress addr = {
-        kAudioHardwarePropertyDefaultOutputDevice,
-        kAudioObjectPropertyScopeGlobal,
-        kAudioObjectPropertyElementMaster
-    };
 
     return AudioObjectGetPropertyData(kAudioObjectSystemObject,
-                                      &addr,
+                                      &voice_addr,
                                       0,
                                       NULL,
                                       &size,
@@ -253,17 +257,8 @@ static void GCC_FMT_ATTR (3, 4) coreaudio_logerr2 (
     coreaudio_logstatus (status);
 }
 
-static inline UInt32 isPlaying (AudioDeviceID outputDeviceID)
-{
-    OSStatus status;
-    UInt32 result = 0;
-    status = coreaudio_get_isrunning(outputDeviceID, &result);
-    if (status != kAudioHardwareNoError) {
-        coreaudio_logerr(status,
-                         "Could not determine whether Device is playing\n");
-    }
-    return result;
-}
+#define coreaudio_playback_logerr(status, ...) \
+    coreaudio_logerr2(status, "playback", __VA_ARGS__)
 
 static int coreaudio_lock (coreaudioVoiceOut *core, const char *fn_name)
 {
@@ -336,6 +331,11 @@ static OSStatus audioDeviceIOProc(
         return 0;
     }
 
+    if (inDevice != core->outputDeviceID) {
+        coreaudio_unlock (core, "audioDeviceIOProc(old device)");
+        return 0;
+    }
+
     frameCount = core->audioDevicePropertyBufferFrameSize;
     pending_frames = hw->pending_emul / hw->info.bytes_per_frame;
 
@@ -368,175 +368,320 @@ static OSStatus audioDeviceIOProc(
     return 0;
 }
 
-static int coreaudio_init_out(HWVoiceOut *hw, struct audsettings *as,
-                              void *drv_opaque)
+static OSStatus init_out_device(coreaudioVoiceOut *core)
 {
     OSStatus status;
-    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
-    int err;
-    const char *typ = "playback";
     AudioValueRange frameRange;
-    Audiodev *dev = drv_opaque;
-    AudiodevCoreaudioPerDirectionOptions *cpdo = dev->u.coreaudio.out;
-    int frames;
-    struct audsettings obt_as;
-
-    /* create mutex */
-    err = pthread_mutex_init(&core->mutex, NULL);
-    if (err) {
-        dolog("Could not create mutex\nReason: %s\n", strerror (err));
-        return -1;
-    }
-
-    obt_as = *as;
-    as = &obt_as;
-    as->fmt = AUDIO_FORMAT_F32;
-    audio_pcm_init_info (&hw->info, as);
 
     status = coreaudio_get_voice(&core->outputDeviceID);
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ,
-                           "Could not get default output Device\n");
-        return -1;
+        coreaudio_playback_logerr (status,
+                                   "Could not get default output Device\n");
+        return status;
     }
     if (core->outputDeviceID == kAudioDeviceUnknown) {
-        dolog ("Could not initialize %s - Unknown Audiodevice\n", typ);
-        return -1;
+        dolog ("Could not initialize playback - Unknown Audiodevice\n");
+        return status;
     }
 
     /* get minimum and maximum buffer frame sizes */
     status = coreaudio_get_framesizerange(core->outputDeviceID,
                                           &frameRange);
+    if (status == kAudioHardwareBadObjectError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ,
-                           "Could not get device buffer frame range\n");
-        return -1;
+        coreaudio_playback_logerr (status,
+                                    "Could not get device buffer frame range\n");
+        return status;
     }
 
-    frames = audio_buffer_frames(
-        qapi_AudiodevCoreaudioPerDirectionOptions_base(cpdo), as, 11610);
-    if (frameRange.mMinimum > frames) {
+    if (frameRange.mMinimum > core->frameSizeSetting) {
         core->audioDevicePropertyBufferFrameSize = (UInt32) frameRange.mMinimum;
         dolog ("warning: Upsizing Buffer Frames to %f\n", frameRange.mMinimum);
-    } else if (frameRange.mMaximum < frames) {
+    } else if (frameRange.mMaximum < core->frameSizeSetting) {
         core->audioDevicePropertyBufferFrameSize = (UInt32) frameRange.mMaximum;
         dolog ("warning: Downsizing Buffer Frames to %f\n", frameRange.mMaximum);
     } else {
-        core->audioDevicePropertyBufferFrameSize = frames;
+        core->audioDevicePropertyBufferFrameSize = core->frameSizeSetting;
     }
 
     /* set Buffer Frame Size */
     status = coreaudio_set_framesize(core->outputDeviceID,
                                      &core->audioDevicePropertyBufferFrameSize);
+    if (status == kAudioHardwareBadObjectError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ,
-                           "Could not set device buffer frame size %" PRIu32 "\n",
-                           (uint32_t)core->audioDevicePropertyBufferFrameSize);
-        return -1;
+        coreaudio_playback_logerr (status,
+                                    "Could not set device buffer frame size %" PRIu32 "\n",
+                                    (uint32_t)core->audioDevicePropertyBufferFrameSize);
+        return status;
     }
 
     /* get Buffer Frame Size */
     status = coreaudio_get_framesize(core->outputDeviceID,
                                      &core->audioDevicePropertyBufferFrameSize);
+    if (status == kAudioHardwareBadObjectError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ,
-                           "Could not get device buffer frame size\n");
-        return -1;
+        coreaudio_playback_logerr (status,
+                                    "Could not get device buffer frame size\n");
+        return status;
     }
-    hw->samples = (cpdo->has_buffer_count ? cpdo->buffer_count : 4) *
-        core->audioDevicePropertyBufferFrameSize;
+    core->hw.samples = core->bufferCount * core->audioDevicePropertyBufferFrameSize;
 
     /* get StreamFormat */
     status = coreaudio_get_streamformat(core->outputDeviceID,
                                         &core->outputStreamBasicDescription);
+    if (status == kAudioHardwareBadObjectError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ,
-                           "Could not get Device Stream properties\n");
+        coreaudio_playback_logerr (status,
+                                    "Could not get Device Stream properties\n");
         core->outputDeviceID = kAudioDeviceUnknown;
-        return -1;
+        return status;
     }
 
     /* set Samplerate */
-    core->outputStreamBasicDescription.mSampleRate = (Float64) as->freq;
-
     status = coreaudio_set_streamformat(core->outputDeviceID,
                                         &core->outputStreamBasicDescription);
+    if (status == kAudioHardwareBadObjectError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError) {
-        coreaudio_logerr2 (status, typ, "Could not set samplerate %d\n",
-                           as->freq);
+        coreaudio_playback_logerr (status,
+                                   "Could not set samplerate %lf\n",
+                                   core->outputStreamBasicDescription.mSampleRate);
         core->outputDeviceID = kAudioDeviceUnknown;
-        return -1;
+        return status;
     }
 
     /* set Callback */
     core->ioprocid = NULL;
     status = AudioDeviceCreateIOProcID(core->outputDeviceID,
                                        audioDeviceIOProc,
-                                       hw,
+                                       &core->hw,
                                        &core->ioprocid);
+    if (status == kAudioHardwareBadDeviceError) {
+        return 0;
+    }
     if (status != kAudioHardwareNoError || core->ioprocid == NULL) {
-        coreaudio_logerr2 (status, typ, "Could not set IOProc\n");
+        coreaudio_playback_logerr (status, "Could not set IOProc\n");
         core->outputDeviceID = kAudioDeviceUnknown;
-        return -1;
+        return status;
     }
 
     return 0;
 }
 
-static void coreaudio_fini_out (HWVoiceOut *hw)
+static void fini_out_device(coreaudioVoiceOut *core)
 {
     OSStatus status;
-    int err;
-    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
+    UInt32 isrunning;
 
     /* stop playback */
-    if (isPlaying(core->outputDeviceID)) {
-        status = AudioDeviceStop(core->outputDeviceID, core->ioprocid);
+    status = coreaudio_get_isrunning(core->outputDeviceID, &isrunning);
+    if (status != kAudioHardwareBadObjectError) {
         if (status != kAudioHardwareNoError) {
-            coreaudio_logerr(status, "Could not stop playback\n");
+            coreaudio_logerr(status,
+                             "Could not determine whether Device is playing\n");
+        }
+
+        if (isrunning) {
+            status = AudioDeviceStop(core->outputDeviceID, core->ioprocid);
+            if (status != kAudioHardwareBadDeviceError && status != kAudioHardwareNoError) {
+                coreaudio_logerr(status, "Could not stop playback\n");
+            }
         }
     }
 
     /* remove callback */
     status = AudioDeviceDestroyIOProcID(core->outputDeviceID,
                                         core->ioprocid);
-    if (status != kAudioHardwareNoError) {
+    if (status != kAudioHardwareBadDeviceError && status != kAudioHardwareNoError) {
         coreaudio_logerr(status, "Could not remove IOProc\n");
     }
     core->outputDeviceID = kAudioDeviceUnknown;
-
-    /* destroy mutex */
-    err = pthread_mutex_destroy(&core->mutex);
-    if (err) {
-        dolog("Could not destroy mutex\nReason: %s\n", strerror (err));
-    }
 }
 
-static void coreaudio_enable_out(HWVoiceOut *hw, bool enable)
+static void update_device_playback_state(coreaudioVoiceOut *core)
 {
     OSStatus status;
-    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
+    UInt32 isrunning;
 
-    if (enable) {
+    status = coreaudio_get_isrunning(core->outputDeviceID, &isrunning);
+    if (status != kAudioHardwareNoError) {
+        if (status != kAudioHardwareBadObjectError) {
+            coreaudio_logerr(status,
+                             "Could not determine whether Device is playing\n");
+        }
+
+        return;
+    }
+
+    if (core->enabled) {
         /* start playback */
-        if (!isPlaying(core->outputDeviceID)) {
+        if (!isrunning) {
             status = AudioDeviceStart(core->outputDeviceID, core->ioprocid);
-            if (status != kAudioHardwareNoError) {
+            if (status != kAudioHardwareBadDeviceError && status != kAudioHardwareNoError) {
                 coreaudio_logerr (status, "Could not resume playback\n");
             }
         }
     } else {
         /* stop playback */
-        if (isPlaying(core->outputDeviceID)) {
+        if (isrunning) {
             status = AudioDeviceStop(core->outputDeviceID,
                                      core->ioprocid);
-            if (status != kAudioHardwareNoError) {
+            if (status != kAudioHardwareBadDeviceError && status != kAudioHardwareNoError) {
                 coreaudio_logerr(status, "Could not pause playback\n");
             }
         }
     }
 }
 
+static OSStatus handle_voice_change(
+    AudioObjectID in_object_id,
+    UInt32 in_number_addresses,
+    const AudioObjectPropertyAddress *in_addresses,
+    void *in_client_data)
+{
+    OSStatus status;
+    coreaudioVoiceOut *core = in_client_data;
+
+    if (coreaudio_lock(core, __func__)) {
+        abort();
+    }
+
+    if (core->outputDeviceID) {
+        fini_out_device(core);
+    }
+
+    status = init_out_device(core);
+    if (!status) {
+        update_device_playback_state(core);
+    }
+
+    coreaudio_unlock (core, __func__);
+    return status;
+}
+
+static int coreaudio_init_out(HWVoiceOut *hw, struct audsettings *as,
+                              void *drv_opaque)
+{
+    OSStatus status;
+    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
+    int err;
+    Audiodev *dev = drv_opaque;
+    AudiodevCoreaudioPerDirectionOptions *cpdo = dev->u.coreaudio.out;
+    struct audsettings obt_as;
+
+    /* create mutex */
+    err = pthread_mutex_init(&core->mutex, NULL);
+    if (err) {
+        dolog("Could not create mutex\nReason: %s\n", strerror (err));
+        goto mutex_error;
+    }
+
+    if (coreaudio_lock(core, __func__)) {
+        goto lock_error;
+    }
+
+    obt_as = *as;
+    as = &obt_as;
+    as->fmt = AUDIO_FORMAT_F32;
+    audio_pcm_init_info (&hw->info, as);
+
+    core->frameSizeSetting = audio_buffer_frames(
+        qapi_AudiodevCoreaudioPerDirectionOptions_base(cpdo), as, 11610);
+
+    core->bufferCount = cpdo->has_buffer_count ? cpdo->buffer_count : 4;
+    core->outputStreamBasicDescription.mSampleRate = (Float64) as->freq;
+
+    status = AudioObjectAddPropertyListener(kAudioObjectSystemObject,
+                                            &voice_addr, handle_voice_change,
+                                            core);
+    if (status != kAudioHardwareNoError) {
+        coreaudio_playback_logerr (status,
+                                   "Could not listen to voice property change\n");
+        goto listener_error;
+    }
+
+    if (init_out_device(core)) {
+        goto device_error;
+    }
+
+    coreaudio_unlock(core, __func__);
+    return 0;
+
+device_error:
+    status = AudioObjectRemovePropertyListener(kAudioObjectSystemObject,
+                                               &voice_addr,
+                                               handle_voice_change,
+                                               core);
+    if (status != kAudioHardwareNoError) {
+        coreaudio_playback_logerr(status,
+                                  "Could not remove voice property change listener\n");
+    }
+
+listener_error:
+    coreaudio_unlock(core, __func__);
+
+lock_error:
+    err = pthread_mutex_destroy(&core->mutex);
+    if (err) {
+        dolog("Could not destroy mutex\nReason: %s\n", strerror (err));
+    }
+
+mutex_error:
+    return -1;
+}
+
+static void coreaudio_fini_out (HWVoiceOut *hw)
+{
+    OSStatus status;
+    int err;
+    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
+
+    if (coreaudio_lock(core, __func__)) {
+        abort();
+    }
+
+    status = AudioObjectRemovePropertyListener(kAudioObjectSystemObject,
+                                               &voice_addr,
+                                               handle_voice_change,
+                                               core);
+    if (status != kAudioHardwareNoError) {
+        coreaudio_logerr(status, "Could not remove voice property change listener\n");
+    }
+
+    fini_out_device(core);
+
+    coreaudio_unlock(core, __func__);
+
+    /* destroy mutex */
+    err = pthread_mutex_destroy(&core->mutex);
+    if (err) {
+        dolog("Could not destroy mutex\nReason: %s\n", strerror (err));
+    }
+}
+
+static void coreaudio_enable_out(HWVoiceOut *hw, bool enable)
+{
+    coreaudioVoiceOut *core = (coreaudioVoiceOut *) hw;
+
+    if (coreaudio_lock(core, __func__)) {
+        abort();
+    }
+
+    core->enabled = enable;
+    update_device_playback_state(core);
+
+    coreaudio_unlock(core, __func__);
+}
+
 static void *coreaudio_audio_init(Audiodev *dev)
 {
     return dev;
-- 
2.24.3 (Apple Git-128)

Re: [PATCH 1/2] coreaudio: Drop support for macOS older than 10.6

[Gerd Hoffmann]

On Mon, Mar 01, 2021 at 08:45:53PM +0900, Akihiko Odaki wrote:
> Mac OS X 10.6 was released in 2009.

Also minimum version required my qemu is 10.13 (I think),
so any code for older macos versions is dead anyway.

take care,
  Gerd

Re: [PATCH 2/2] coreaudio: Handle output device change

[Gerd Hoffmann]

  Hi,

>      status = coreaudio_get_voice(&core->outputDeviceID);
>      if (status != kAudioHardwareNoError) {
> -        coreaudio_logerr2 (status, typ,
> -                           "Could not get default output Device\n");
> -        return -1;
> +        coreaudio_playback_logerr (status,
> +                                   "Could not get default output Device\n");
> +        return status;

This "pass status code to caller" change can and should be splitted to a
separate patch.

Likewise with the logging changes.

That makes the patch with the actual functional change to deal with the
device changes smaller and easier to review.

thanks,
  Gerd

Re: [PATCH 2/2] coreaudio: Handle output device change

[Akihiko Odaki]

2021年3月3日(水) 18:27 Gerd Hoffmann <kraxel@redhat.com>:
>
>   Hi,
>
> >      status = coreaudio_get_voice(&core->outputDeviceID);
> >      if (status != kAudioHardwareNoError) {
> > -        coreaudio_logerr2 (status, typ,
> > -                           "Could not get default output Device\n");
> > -        return -1;
> > +        coreaudio_playback_logerr (status,
> > +                                   "Could not get default output Device\n");
> > +        return status;
>
> This "pass status code to caller" change can and should be splitted to a
> separate patch.
>
> Likewise with the logging changes.
>
> That makes the patch with the actual functional change to deal with the
> device changes smaller and easier to review.
>
> thanks,
>   Gerd
>

Actually the code was extracted from coreaudio_init_out to
init_out_device in this patch. init_out_device "passes status code to
caller", but coreaudio_init_out still doesn't. A new executor of the
procedure, handle_voice_change only uses the status code returned by
init_out_device.

Logging changes are alike; Now "playback" type logs are recorded by
both of coreaudio_init_out and handle_voice_change.
handle_voice_change is a function required only for device change.

Regards,
Akihiko Odaki

Re: [PATCH 2/2] coreaudio: Handle output device change

[Gerd Hoffmann]

On Wed, Mar 03, 2021 at 10:20:20PM +0900, Akihiko Odaki wrote:
> 2021年3月3日(水) 18:27 Gerd Hoffmann <kraxel@redhat.com>:
> >
> >   Hi,
> >
> > >      status = coreaudio_get_voice(&core->outputDeviceID);
> > >      if (status != kAudioHardwareNoError) {
> > > -        coreaudio_logerr2 (status, typ,
> > > -                           "Could not get default output Device\n");
> > > -        return -1;
> > > +        coreaudio_playback_logerr (status,
> > > +                                   "Could not get default output Device\n");
> > > +        return status;
> >
> > This "pass status code to caller" change can and should be splitted to a
> > separate patch.
> >
> > Likewise with the logging changes.
> >
> > That makes the patch with the actual functional change to deal with the
> > device changes smaller and easier to review.
> >
> > thanks,
> >   Gerd
> >
> 
> Actually the code was extracted from coreaudio_init_out to
> init_out_device in this patch.

It is likewise good practice to handle such refactorings as separate
patch, i.e. have a patch which reorganizes the code (in this case move
code to the new init_out_device() function) without functional change,
then go add the new handle_voice_change which fixes the actual issue
in the next patch.  Finally send the two (or more) changes as patch
series.

take care,
  Gerd